Electric fuse and method of assembling same



Nov. '10, 1931. J. A. BUSSMANN 1,831,438

ELECTRIC FUSE AND METHOD OF ASSEMBLI NG SAME Filed Dec. 13, 1926,

. IVNVENTOR JOStZ'RH/ZBUJJHHNN ATTORNEY Patented Nov. 10, 1931 PATENTorrlcs JOSEPH A. BUSSIEANN, OF ST. LOUIS, MISSOURI ELECTRIC FUSE ANDMETHOD OF ASSEMBLING SAME Application filed December 13,1926. Serial No.154,539.

My invention relates to ferrule contact type electric fuses, and theobject of my invention 1 is-to provide an efiicient fuse and a method ofassembling the same which will materially 5 reduce the cost ofmanufacture without any I detraction from the efliciency of orprotection afforded by the fuse.

These advantages of my invention will be readily understood by referringto the accompanying' drawings which show a preferred embodiment of myinvention.

Fig. 1 shows aferrule contact fuse. Fig. 2 shows a cross sectional Viewof the longitudinal section thereof along the axis.

5 In the drawings 1 and 2 show metallic ferrule terminals attached tothe ends of the insulating tube, 3. These terminals serve the doublepurpose of connecting the fuse to the electrical circuit and forming inconjunction with the tube an enclosure for the fusible element 4, whichis electrically and mechanically connected to the ferrules by solder orotherwise.

In assembling a fuse of this type the ferrules are usually attached tothe tube. The link 4, is then inserted through holes 7 and Sin theferrules and soldered to the ferrules. These holes 7 and 8 have adiameter not sub- 7 stantially greater than the diameter of the link, soas to make easy the soldering operation and to reduce to a minimum theamount of solder necessary.

Heretofore considerable difiiculty and expense have been incident toinserting the link in proper position for soldering. With links havingboth ends of the same dimensions and a length approximately the same asthe fuse, considerable difficulty was experienced in endeavoring to getthe linkproperly placed 4 0 through the hole in the second ferrule afterhaving passed it through the first one; nor was this difficulty lessenedby putting on one of the ferrules first, then inserting the link andthen putting. on the other ferrule, be-

cause of the difficulty of getting and holding the link exactly in thecenter while the second ferrule was being placed in position.

For these reasons it has usually been customary length of the fuse sothat the operator could to make the link longer than the.

hold the link after it had been passed through the first ferrule andadjust it in position in the second ferrule, or, if the link werefastened to the one ferrule, and then the tube and second ferruleslipped over the link, it 65 was possible, because of the extra lengthof the link, to first get the link through the hole in the secondferrule before putting the ferrule in position. The extra length of linkwould then have to be cut off before or after soldering to ,the secondferrule. This method necessitates an extra operation and waste of thelink material cut oil".

The object of my invention is the elimination of these difficulties andthe extra operation referred to as well as the waste of materialreferred to, which object I accomplished by making one end of the link,4, of such form or size, preferably by increasing the width as shown at5, that it will not pass through the hole 7 in ferrule 1 while at thesame time I make the other end of the link of reduced width and roundedor tapered as shown at 6 so that it will easily pass into thecorresponding hole 8 of ferrule 2. V

I find that with this construction if the ferrules are first attached tothe tube and then the link inserted it is readily possible to drop thelink through the hole 7 of ferrule 1 and that the rounded end 6 easilylocates itself in the hole 8 of ferrule 2.

It is obvious that with this construction the link need not be longerthan the fuse and that the cutting off operation and consequent waste ofmaterial are both eliminated.

In the case of fuses which have the link attached with solder, theferrules are usually depressed and the solder used fills these .de-

pressions around the ends of the links as t shown at 9, 10.

With this particular type of link the operation of assembly is very muchmore rapid thereby considergxly lowering the cost of manufacture. I

It is obvious that instead of making one end of the "link wide toprevent its passing thru the hole 7 that many other methods may be usedto accomplish the same result.

What I claim 1s 1. The herein before described method of making anenclosed, ferrule contact type fuse, which consists in forming a fuselink substantially the length of the enclosure and forming one end ofthe link so as not to pass through the ferrule and with the other endreduced, and in passing the link through openings in the ferrules andsoldering the link therein.

2. The herein before described method of making an enclosed,ferrulecontact type fuse,

said ferrules having link receiving openings which consists in forming afuse passage through the enclosure, in standing the enclosure on end andin forming a link of substantially the same length as the enclosure, inreducing one end portion of the link, and inserting the link through theopening in the top ferrule into said passage so that its reduced portioncomes into engagement with the lower ferrule contact with the link infinal position with respect to the ferrule contacts, and thereaftersoldering the link to the ferrule contacts.

3. In a fuse, a link, a tube, and caps at tached to said tube, eachcap'having a depression therein and having an opening through itsdepressed portion through'which the link extends, said link having alateral projection at one end and a reduced portion at its op'positeend, said ends being surrounded by solder located in said depressionsfor electrically connecting said link to said caps.

4. In a fuse, a casing including a tube and metal end members on saidtube, each end member having a recess and alink-opening through saidrecess, a link having a maximum width between its ends, notsubstantially less than the width of the link openings, and hav-' ing alaterally projecting portion at one end and a reduced portion at itsopposite end, said portions spaced substantially to conform to thedistance between'said recesses, and not substantially greater than thelength of said casing, and means metallically uniting said link portionsto the recessed portions of the end members. i

5. In a fuse, a link, a casing including a tube and metal caps at theends of the tube, each cap having a depression with a linkopeningtherethrough, a unitary fuse link having a maximum width between itsends not substantially less than the width of the link opening andformed with its ends lying in said depressions and soldered thereto, oneof said link ends being of reduced sectional area.

JOSEPH A. BUSSMANN.

